Guiding comb tooth for air jet looms

ABSTRACT

A guiding comb tooth for air jet weaving looms, the body of which comb tooth forks into a straight part and an arcuate part, such parts together forming a substantially circular picking aperture for the weft thread and leaving an exit slot for the weft thread from the picking aperture; the exit slot is closed at its entrance by flat spring means fixed on the arcuate part of the comb tooth and leaning against the internal wall of the straight part of this comb tooth.

United States Patent 11 1 1111 3,742,973

V Kakac 1 July 3, 1973 GUIDING COMB TOOTH FOR AIR JET LOOMS Primary Examiner-Henry S. Jaudon [75] Inventor: Karel Kakc Brno. Czechoslovakia A"0mey Arthur Klem [73] Assignee: Vyzkumny d vyvojovy ustav Zavodu VSQObCCIIQkO Stl'OjiI'GllSIVi, Brno, 5 7 Czechoslovakia [22] Filed: Feb- 8 1972 A guiding comb tooth for air jet weaving looms. the body of which comb tooth forks into a straight part and PP 224,418 an arcuate part, such parts together forming a substantially circular picking aperture for the weft thread and 52 US. Cl. 139/127 P leaving an the thread from Picking 51 Int. Cl 003d 47/28 aperture; the is clsed at its entrance by [58] Field of Search 139/188 R 127 P Spring means fixed the arcuate P of comb tooth and leaning against the internal wall of the 56] References Cited straight part of this comb tooth.

FOREIGN PATENTS OR APPLICATIONS Italy 1. l39/l27 7 Claims, 4 Drawing Figures GUIDING COMB TOOTH FOR AIR JET LOOMS BACKGROUND OF THE INVENTION This invention relates to improvements in a guiding comb tooth for an air jet weaving loom and the object of this invention is to increase the efficiency of such guiding comb and to permit an increase of the picking width of the loom while maintaining a reliable penetration of the guiding comb into the respective system of warp threads without causing defects.

Earlier proposed jet looms where the weft thread is picked through by means of pressure air, were provided for guiding of such air stream and of the weft with a guiding comb, havinga system of teeth spaced a certain mutual distance, said teeth preferably having a socket fixed on the batten, forking into a straight part, by means of which the comb tooth enters the system of warp threads forming the loom shed, and into an arcuate part, the internal wall of which forming a part of the picking channel, having substantially a circular crosssection, passing over toward the top of the straight part in an inclined direction and leaving an exit slot between the top of the straight part and the top of the arcuate part, through which the weft, after being picked through, is removed from the guiding comb prior to being beaten up by the batten and in the course of removal of the guiding comb from the shed.

It is furthermore known to provide the aperture of the comb tooth with a frusto-conical surface, with the apex of such surface pointing in the direction of weft picking, in order to concentrate the air stream in the center of the aperture of the comb tooth and to reduce to a minimum the losses of energy of the air stream passing from one tooth to the next one.

Another known comb tooth has straight and arcuate parts with a wedge shaped external circumference in order to facilitate entrance of the comb teeth into the system of warp threads and a correct separation of adjacent warp threads with a minimum friction.

In a further proposed solution for the reduction of the losses of energy of the air stream taking place along the weft, the weft exit slots had a labyrinth form. This arrangement, however, caused technological difficulties which were not compensated for by the reduction of losses of energy of the air stream.

Another solution proposed a comb tooth of a small circular shape, covered by a flat spring contacting the open front surface of the tooth. This flat spring completes the circumference of the picking opening of the tooth during the entrance of the comb teeth into the shed, during picking through the weft, and in the course of a major part of the following operation, forming a picking channel, whereby only in the course of removal of the weft thread from this picking channel is the upper part of the flat spring lifted due to the motion of the guiding comb relative to the picked through weft thread. This arrangement has a number of drawbacks, the most serious being that the comb tooth enters the system of warp threads, not by its wedge-shaped part, but by its flat part having the width of the flat spring, so that the separation of the warp threads in the course of entrance of the guiding comb into the shed over the system of warp threads is rather forcible and causes frequent damages and breakage of individual warp threads.

Another drawback of this arrangement is the impossibility of providing the part of the picking aperture, formed by said spring, with a frusto-conical wall required for concentrating the air stream in the center of the picking aperture; as a result, the reduction of losses of energy obtained by an uninterrupted circumference of the picking aperture obtained by the sealing by means of said spring is reduced by an increase of stray losses of the air stream. Another substantial drawback of this comb tooth is its complicated manufacture, as it is composed of three major parts: a body with a semicircular opening, a flat spring, and a fastening screw, rivet or the like. If no substantial damage should be caused to the weft threads in the course of their removal from the comb teeth, the flat spring must not be too stiff; if, however, it is too weak, it becomes easily fatigued and it fails to perform its task of perfectly sealing the exit slot. Fatigue of this spring is caused by its rubbing against warp threads, particularly in the course of movement of the guiding comb in the direction of the impact by the reed.

SUMMARY OF THE INVENTION It is an object of this invention to eliminate these drawbacks and to provide an improved arrangement for closing the exit slot of the picking aperture while maintaining all advantages of these comb teeth, that is, both the frusto-conicity of the picking aperture and the easy penetrating of the comb teeth into the system of warp threads forming the shed and particularly also a simplicity of manufacture and low cost of the individual comb teeth.

According to this invention the arcuate part of the comb tooth is provided at a place in front of the exit slot from the picking aperture with flat spring means which can be easily deformed and one end of which completely closes the exit slot from the picking aperture. This flat spring means has advantageously in the extreme position of the comb tooth within the shed an inclination, corresponding to the inclination of the upper system of warp threads forming the shed, whereby the maximum width of said spring means does not surpass the maximum width of the tooth body. The individual teeth are preferably made of one piece of plastic by injection molding.

DESCRIPTION OF THE DRAWINGS Further advantages and features of this invention will be apparent from the following description, referring to the attached drawings in which:

FIG. 1 is a view in elevation of a comb tooth disposed in a fully opened shed that is in the picking through position;

FIG. 2 is a view of a comb in section, the section being taken along a plane indicated in FIG. 1 by the line A-A;

FIG. 3 is a view of a comb in section, the section being taken along a plane indicated in FIG. I by the line 8-8; and

FIG. 4 is an elevation ofa comb in a closing shed and in the first phase of removal of the picked through weft from the picking aperture.

DESCRIPTION OF A PREFERRED EMBODIMENT The body of the comb tooth 1 shown has a body with a stem 2, the body forking in its upper part into a first, straight part 3 and a second, arcuate part 4. The stem 2 of the tooth 1 is fixed in a commonly known manner on a batten (not shown). The top of the straight part 3 of the tooth 1 passes over into a tip 5, whereas the top of the arcuate part 4 of the tooth 1 forms an exit slot 6 and is provided with flat spring means 7 which in FIG. 1 fully contacts the longitudinally straight, transversely tipped internal surface 8 of the straight part 3 of the tooth 1. The packing aperture 9 has nearly the shape of a full circle.

As obvious from FIG. 2, the internal surfaces 9 forming the picking aperture are frusto-conical and disposed at an angle 01/2 with respect to the plane of the tooth in order to concentrate the air stream passing in the direction of the arrow S (FIG. 2) to the center of the picking aperture. As shown in FIG. 3, the frustum formed by the surfaces 9 has an apex angle a and is disposed symmetrically with respect to the broad plate of the tooth.

As can be seen in FIGS. 2 and 3, all external circumferences of the tooth 1, including the straight part 3 and the arcuate part 4 of the tooth, are shaped as a wedge symmetrical with respect to the mid plane of the broad extent of the tooth, in order to penetrate easily into the shed.

FIG. 1 also shows the upper system 10 of warp threads, the lower system 11 of warp threads, and the just picked through weft 12. Furthermore, FIG. 1 shows that the broad extent of flat spring means 7 is substantially parallel with the upper system 10 of warp threads at the time when both systems 10 and 11 of warp threads form a fully open shed.

FIG. 4 shows a tooth 1 and both systems 10 and 11 of warp threads at the moment when the shed is closing and the tooth 1, due to turning of the batten (not shown) upon which it is mounted starts to leave the shed while due to a relative movement of the tooth l with respect to the weft thread 12 the flat spring means 7 is deformed in the direction toward the exit slot 6, thereby enabling the removal of the weft thread 12 from the previously closed picking aperture 9. In the immediately following operating phase the weft thread 12 is removed in a known way from the exit slot 6, the flat spring means 7 then returning to its original position, where it is in contact with the straight internal surface 8 of the straight part 3 of the tooth l.

The tooth 1 is advantageously made of one piece of elastic plastic material, preferably by injection molding in a known mold (not shown) where an exact shape and the required smooth surfaces of the tooth are obtained without any further machining.

The described tooth operates as follows: Let us consider the position of the comb tooth 1 in the open shed formed by the upper system 10 of warp threads and by the lower system 11 of warp threads as shown in FIG. 1. The batten (not shown), is in its extreme rear (right, FIG. 1) position, where the picking through of the weft 12 may proceed by the known stream of pressure air. In the course of this picking through, the continuity of the picking aperture 9 is completed by the flat spring means 7, closing on the longitudinally straight, tipped internal surface 8 of the straight part 3 of the tooth 1.

After the picking through of the weft thread 12 is finished, the batten starts to move to its beating-up position in the direction of the arrow S as indicated in FIGS. 1 and 4, whereby the shed starts to close by approaching both the upper and lower system 10 and 11 of warp threads; simultaneously, the guiding comb with the teeth 1 starts to leave the shed as the teeth 1 pass through the lower system 10 of warp threads in the direction S,.

In the course of a certain phase of this proceeding, by reason of the relative movement between the weft thread 12, the tooth 1, and the lower system 10 of warp threads, the weft thread 12 reaches a position indicated in FIG. 4, wherein the weft thread 12 bends the flat spring means 7 upwards toward the exit slot 6, whereby the free end of the flat spring means 7 is separated from the straight internal surface 8 of the straight part 3 of the tooth 1, thus enabling the weft thread 12 to leave the picking aperture 9, the circumference of which, up to now, has been complete.

As soon as the weft thread 12 passes between the free end of the flat spring means 7 and the straight internal surface-8 of the straight part 3 of the tooth 1, the flat spring means 7, because of its own elasticity, again comes into contact with the straight internal surface 8 of the straight part 3 of the tooth l, and thus again fully closes the circumference of the picking aperture 9 so that the time interval within which pressure air is allowed to escape from the picking aperture 9 is reduced to a minimum.

In the course of the following phases of operation, the weft thread 12 is removed in a known way through the exit slot 6 of the tooth 1 and this tooth leaves (in a manner not shown) the closing weft.

The picked through weft thread 12 is thereafter beaten up by a reed (not shown) followed by a repeated penetrationof the individual teeth 1 of the guiding comb into the again open shed; in the course of this movement the teeth 1 enter the lower system 11 of warp threads by their pointed straight part 3 or by its tip 5. As all external edges of the tooth 1, as shown in FIGS. 2 and 3, are wedge-shaped, the penetration of the lower system 11 of warp threads is accomplished with a minimum of friction and stressing of the warp threads with which the individual teeth 1 come in contact.

Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is respectfully requested that it be understood that it is in no way limited to the recitation of such a preferred embodiment, but is capable of numerous modifications within the scope and spirit of the appended claims.

What is claimed is:

1. A guiding comb tooth for air jet looms, said tooth being adapted to guide a weft thread picked by a stream of pressure air through the open shed of a loom, the shed being formed by an upper system of warp threads and a lower system of warp threads, said guiding comb being adapted to be mounted in said loom in a position determined by a first extreme position beyond the shed, and by a second extreme position within an open shed, said guiding comb comprising a body forking into a substantially straight part and an arcuate guiding comb tooth and thus, when undeformed, closing completely the exit slot of the picking aperture.

2. A guiding comb tooth as set forth in claim 1, wherein said flat spring means, in said second extreme position of the guiding comb tooth within the open shed, is deformed sothat it is inclined, the degree of its inclination with respect to the horizontal corresponding to the inclination from the horizontal of the upper system of warp threads forming the shed.

3. A guiding comb tooth as set forth in claim 1, wherein the width of said flat spring means is at a maximum equal to the width of the guiding comb tooth.

4. A guiding comb tooth as set forth in claim 1,

posed normal to the plane of the body. 

1. A guiding comb tooth for air jet looms, said tooth being adapted to guide a weft thread picked by a stream of pressure air through the open shed of a loom, the shed being formed by an upper system of warp threads and a lower system of warp threads, said guiding comb being adapted to be mounted in said loom in a position determined by a first extreme position beyond the shed, and by a second extreme position within an open shed, said guiding comb comprising a body forking into a substantially straight part and an arcuate part, the outer free ends of the straight and arcuate parts approaching each other but leaving an exit slot for the weft thread between them, said straight and arcuate parts together forming a substantially circular picking aperture below said exit slot for picking through the weft thread, deformable flat spring means provided on said arcuate part in front of the exit slot, the outer end of said flat spring means leaning against the internal wall of the substantially straight part of the guiding comb tooth and thus, when undeformed, closing completely the exit slot of the picking aperture.
 2. A guiding comb tooth as set forth in claim 1, wherein said flat spring means, in said second extreme position of the guiding comb tooth within the open shed, is deformed so that it is inclined, the degree of its inclination with respect to the horizontal corresponding to the inclination from the horizontal of the upper system of warp threads forming the shed.
 3. A guiding comb tooth as set forth in claim 1, wherein the width of said flat spring means is at a maximum equal to the width of the guiding comb tooth.
 4. A guiding comb tooth as set forth in claim 1, wherein the comb tooth with said flat spring means is made in one piece.
 5. A guiding comb tooth as set forth in claim 4, wherein the one-piece tooth is molded of plastic material.
 6. A guiding comb tooth as set forth in claim 1, wherein the picking aperture through the tooth is of frusto-conical shape.
 7. A guiding comb tooth as set forth in claim 6, wherein the tooth has a plate-like body, and the axis of the frusto-conical picking aperture therethrough is disposed normal to the plane of the body. 